Conventional polyacrylic acid-based fiberglass insulation binders are typically manufactured with a low molecular weight polyacrylic acid, a polyhydroxy crosslinking agent, and a cure accelerator, such as sodium hypophosphite. Typical commercial embodiments include QRXP-1564 and QRXP-1513, produced by Rohm & Haas. QRXP-1564 is a blend of Acumer 1020 (71.6 wt-%), glycerol (21.8 wt-%), sodium hypophosphite (5.6 wt-%), and a small amount of corrosion inhibitor. Water is added as a diluent. QRXP-1513 is a blend of Acumer 1020, triethanolamine, and sodium hypophosphite. Water is added as a diluent. Acumer 1020 is a polyacrylic acid produced from acrylic acid monomer and a sodium bisulfite reactant. Acumer 1020 has a molecular weight of approximately 2000 and a sulfur content of about 3.4 wt-%. U.S. Pat. Nos. 5,340,868, 5,661,213, and 5,763,524, as well as PCT publications WO 100 699 A2 and WO 9 961 384 A1, disclose conventional sulfur-containing polyacrylic acid-based fiberglass insulation binders.
The low molecular weight polyacrylic acid used for the above binders normally is prepared by aqueous polymerization, the polymerization being regulated with sodium bisulfite or a similar sulfite compound to give the desired molecular weight. During high temperature oven cure procedures, the polyacrylic acid-based binder tends to emit sulfur odors, which are trapped within the insulation product. This results in an undesired odor profile during product packaging in production and fabrication operations.
U.S. Pat. No. 5,318,990 discloses fibrous glass binders comprising the reaction product of a polycarboxy polymer, a monomeric trihydric alcohol, and a catalyst comprising an alkali metal salt of a phosphorous-containing organic acid. The present invention, in contrast, reacts a low molecular weight polyacrylic acid polymer with a monomeric trihydric alcohol in the absence of added catalyst.